An elevator having two elevator cars is known from WO 2005/014461 A1, the two elevator cars being coupled to each other in such a way that they can be moved together in an elevator shaft. A vertical separation between the two elevator cars can be adjusted by moving at least one elevator car in relation to the other elevator car. An adjustment cable serves to do this. One end of the adjustment cable is attached at the end to the shaft floor. A counterweight hangs from the other end. In addition, the adjustment cable is guided via a traction sheave of an adjustment drive that includes an elevator machine. An additional elevator machine is also provided that serves to move the whole assembly, including both elevator cars, through the elevator shaft.
The elevator system known from WO 2005/014461 A1 has the disadvantage that it broadly requires two complete assemblies having elevator machinery and counterweights as well as the required deflection rollers in order to realize the joint motion of both elevator cars through the elevator shaft as well as the adjusting mechanisms of both elevator cars to each other. Powerful elevator machinery is also required here because, for example, the complete load of the assembly must be moved through the elevator shaft just by the additional elevator machine. In addition to the high expense for the large number of powerful components, they also result in a larger space requirement and higher construction expenditures in the realization.
In the realization of a custom adjustment mechanism for adjusting the two elevator cars to one another, it is conceivable that the components for these adjustment mechanisms are mounted on the elevator car frames. This design has the disadvantage, however, that the drive for the adjusting mechanism, in particular, can also be mounted on the elevator car frame and the elevator machine that is required to move the assembly of elevator cars in addition to the adjustment mechanism must be designed to be more effective. The mass of the counterweight needed for this is also greater.
JP H11228057 and JP 2001080856 also describe elevators having two elevator cars in one car assembly that are adjustable relative to one another. The corresponding adjustment mechanisms have two adjustment traction means that are connected to an elevator car on one side and to a counterweight on the other.